Investigation of Hysteresis-based State Feedback Controller for Grid-Interfaced Power Converters

Grid-interfaced power converters are increasingly dominating electrical power grids at generation, transmission and consumption level. Especially contributed by the large-scale integration of distributed renewable energy resources to meet the worldwide ambitious goal of a sustainable future of energy supply, nowadays and future grid operators face emerging power quality and system stability issues. Grid-interfaced power converters are expected to provide ancillary system services and comply with even stricter grid code requirements. As hysteresis controllers still enjoy a great popularity, their distinctive switching frequency spectrum deteriorates the system performance. Particularly in high-power applications, switching frequencies need to be properly limited to avoid thermal loading. On the other side, low-order switching harmonics are equally undesired as system resonances due to LCL filters are excited. This paper evaluates a hysteresis-based current control approach for grid-interfaced power converters with regard to aforementioned practical issues. Experimental results demonstrate improved steady-state and dynamic performance featuring active damping capabilities and nearly constant average switching frequencies.